As of late April, Mississippi soybeans were 60 percent planted. Growers will put the final touches on the crop as soon as fields dry, except for wheat ground.
Since planting began in mid-April, I have observed excellent emergence. The use of proper seed treatments made a difference for some, but not as much on the early plantings as you might expect, particularly where rainfall was sporadic.
I think many farmers have observed the benefits of a pythium-based seed treatment program. The benefit, however, depends on whether or not it rains. Even though an Apron-based program can help, 7 to 11 inches of rain may be too much. Most of the rain ran off, but moisture is the element needed to trigger an infection from pythium.
I have looked at several fields where emergence was less than desired, but the difference between these stands and a total loss was the use of a seed treatment program that controlled pythium.
In one field where an Apron-type material was not used, the producer had a skippy stand. The farmer told me he planted on a Wednesday with a good forecast (no rain in sight), but it rained on Thursday, and he was going to have to replant. It does not matter if it is cool or warm; what does make is when it is going to rain. Moisture is the key.
Pythium has to have moisture to thrive. In most cases it thrives under cool, wet conditions. However, the late Bob Keeling identified a hot-weather pythium (Pythium aphanidermatum) that is so severe it will make you wonder if we even have a problem with pythium early.
Seed treatments are insurance. Seed protectants such as Thiram and products active against rhizoctonia are beneficial. Pythium, however, is the main organism we encounter in most replant situations.
The uncertainty of seedling disease has prompted us to recommend a broad spectrum seed treatment program.
A seed treatment may not produce yield increases directly. The difference in yields comes from avoiding delays in planting. If you planted in mid-April and failed to get a stand, it can be 10 to 14 days before you make the decision to replant.
This year, if you missed the mid-April window in the north Delta, your planting would have been delayed until mid-May due to wet conditions.
It is a matter of out-guessing the weather. If you know when it is going to rain, you can determine what to use.
I am observing greater-than-expected seed emergence. In most fields I am counting more plants per foot than growers thought they planted. This is not unexpected with high-quality seed and good growing conditions. We can plant fewer seeds per acre than most do.
As you resume planting, keep seeding rates in mind. As you change varieties, seed lots, etc., adjust seeding rates. Set planters on the basis of seed per foot of row, not pounds per acre.
Where emergence has been a problem, it may be due to nothing more than planting depth. As moisture becomes marginal, avoid planting deep early. We had numerous situations where it was dry on top, but moisture was available at depths greater than 2 inches.
You need moisture for germination to occur, but don’t get caught planting deep early. While temperatures are cool, seed will lay in the ground for an extended time. Prior to early May, if conditions are dry, I would consider planting shallow and waiting on rainfall.
Even if daytime temperatures are reaching 90-plus degrees, seed will remain viable for a long time as long as night-time temperatures are cool.
Avoid placing seed in a marginal moisture scenario. Plant in adequate moisture or plant dry. If seed are planted deep too early and you get the kind of rain we often experience in late-April, replanting is almost a sure thing.
Another area you need to pay particular attention to is no-till planting. The first of May we started seeing grasshoppers. They did not show up as early as last year nor were they as widespread.
I have observed scattered occurrences of bean leaf beetles and cutworms in fields with high numbers of snails and slugs.
This past winter, above-average rainfall (compared to the past two winters) may have helped reduce grasshopper numbers. There is no doubt that tillage made a difference.
All of the unusual problems we are observing are in no-till. Is that a reason to stop? No, but you should prepare to scout fields for these unusual pests.
I think a lot of these pests could be avoided by applying burndown materials early. If these pests emerge and have nothing to feed on, many may leave a field prior to the crop emerging. With the problems associated with heavy residue buildup and late burndowns, it is hard to fathom why more do not prepare earlier.
Alan Blaine is the Mississippi Extension soybean specialist.
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